c2ffi rubocop task

# c2ffi: Clang-based FFI wrapper generator
# https://github.com/rpav/c2ffi

namespace :c2ffi do
  desc 'Generate metadata files (JSON format) using c2ffi'
  task :generate do
    FileUtils.mkdir_p('codegen/c2ffilogs')
    header_files = FileList['■■■/src/*.h']
    header_files.each do |file|
      basename = File.basename(file, '.h')
      system "c2ffi -o codegen/#{basename}.json -M codegen/#{basename}.c #{file}" \
             " 2> codegen/c2ffilogs/#{basename}.log"
    end
  end

  desc 'Remove metadata files'
  task :remove do
    FileList['codegen/*.{json,c}', 'codegen/c2ffilogs/*.log'].each do |path|
      File.unlink(path) if File.exist?(path)
    end
  end
end